This invention relates to a contents processing system for a user to obtain encrypted contents data through electronic distribution.
Recently, there has been data distribution for providing encrypted contents data to a user through electronic distribution using satellite broadcast or the Internet.
In the electronic distribution using satellite broadcast or the Internet, encrypted data is transmitted and received between a data transmission device and a receiving device in order to prevent leakage of the data to a third party. The contents to be electronically distributed include music, images, and works such as programs and texts.
With respect to the contents data such as music and images on which the copyright has been established, free duplication of such contents data even for the personal use may violate the copyright protection. Particularly, duplication of digital data, or so-called digital copy or digital dubbing, enables duplication of contents data without suffering deterioration of signals. Therefore, there need be some restrictions. For example, the audio digital interface prescribed by the IEC958 employs a copy generation restriction system called SCMS (serial copy management system) used in the existing CD (compact disc), DAT (digital audio tape) or MD (mini disc). This system is adapted for describing a copy control code to bits on the digital interface for prohibiting copy of the second and subsequent generations in executing copy for the first time (first generation) to a predetermined recording medium. Specifically, in the SCMS, the SCMS copy control code appended to or embedded in the xe2x80x9cparentxe2x80x9d contents data permits one-generation copy, and the SCMS copy control code is rewritten to prohibit copy with respect to the xe2x80x9cchildxe2x80x9d contents data, which is obtained by sending and digitally duplicating the parent contents data at a duplication destination.
In the case where the service of contents data such as music data is provided through electronic distribution using the Internet or satellite broadcast, in general, the contents data such as music data is encrypted and a key (contents key) used for the encryption is also encrypted by another key (distribution key).
Meanwhile, in the case where one-generation digital duplication of the contents data such as music data can be carried out as in the conventional cases, the copy control code of the xe2x80x9cparentxe2x80x9d contents data permits one-generation copy, and the copy control code of the xe2x80x9cchildxe2x80x9d contents data in the equipment at the duplication destination must be rewritten to prohibit copy.
In the case where the xe2x80x9cparentxe2x80x9d contents data are encrypted, if the equipment at the duplication destination has a function to decode the encrypted data, sending the contents data to the equipment at the duplication destination without decoding is preferred in view of the processing time and labor. However, since the SCMS copy control code embedded in the contents data and thus encrypted together with the contents data, the copy control code embedded and encrypted in the contents data is supplied to the equipment at the duplication destination without having its value changed. On the other hand, if the copy control code is to be rewritten to prohibit copy by the equipment on the supply side, then embedded in the contents data and sent to the equipment at the duplication destination, the contents data must be decrypted to rewrite the copy control code to prohibit copy and the contents data then must be encrypted again. The processing is complicated troublesome.
In general, the size of the contents key is approximately several bytes and the size of the contents data is several hundred kbytes to several Mbytes or even several Gbytes. Therefore, resetting the key takes a very long processing time.
In view of the foregoing status of the art, it is an object of the present invention to provide a contents signal receiving device and a contents processing system which enable efficient embedding of identification information of an equipment used in obtaining contents signals into the contents, when a user obtains encrypted contents signals through electronic distribution and then decodes and outputs contents.
It is another object of the present invention to provide a contents processing device, an encryption processing device and a contents processing system which enable secure accounting when a user obtains and decodes encrypted contents signals through electronic distribution.
It is still another object of the present invention to provide a contents signal receiving method which enables efficient embedding of identification information of an equipment used in obtaining contents signals into the contents, when a user obtains encrypted contents signals through electronic distribution and then decodes and outputs contents.
It is still another object of the present invention to provide a contents processing method which enables secure accounting when a user obtains and decodes encrypted contents signals through electronic distribution.
A contents signal receiving device according to the present invention includes: receiving means for receiving an encrypted contents signal; storage means for storing the encrypted contents signal received by the receiving means; decoding means for decoding the encrypted contents signal stored in the storage means when an instruction to decode the encrypted contents signal stored in the storage means is given as user-designated information; and identification information appending means for appending identification information to the contents signal decoded by the decoding means.
Also, a contents signal receiving device according to the present invention includes: receiving means for receiving an encrypted contents signal and identification information from an external device; decoding means for decoding the encrypted contents signal; and identification information appending means for appending identification information to the contents signal decoded by the decoding means.
Also, a contents processing device according to the present invention includes: decoding means for decoding an encrypted contents signal using a contents key; log information generation means for generating log information every time the contents key is decoded by the decoding means; storage means for storing the log information; and transmission means for transmitting the log information at predetermined timing.
Also, a contents processing device according to the present invention includes: receiving means for receiving an encrypted contents key obtained by encrypting a contents key for decoding an encrypted contents signal by using a distribution key updated every predetermined period; decoding means for decoding the encrypted contents signal by the contents key; accounting information generation means for generating accounting information concerning the use of the encrypted contents signal; storage means for storing the accounting information; and transmission means for transmitting the accounting information when the distribution key is updated.
Also, a contents processing device according to the present invention includes: receiving means for receiving a distribution key, which is a key for decoding an encrypted contents signal and is updated every predetermined period; decoding means for decoding the encrypted contents signal on the basis of the distribution key; accounting information generation means for generating accounting information concerning the use of the encrypted contents signal; storage means for storing the accounting information; and transmission means for transmitting the accounting information when the distribution key is updated.
Also, an encryption processing device according to the present invention includes: decoding means for decoding an encrypted contents key obtained by encrypting a contents key for decoding a contents signal; log information generation means for generating log information every time the contents key is decoded; encryption means for encrypting the contents key by a save key; and a one-chip module internally storing the decoding means, the log information generation means and the encryption means.
Also, a contents processing system according to the present invention includes: a first contents processing device including storage means for storing an encrypted contents signal, storage means for storing identification information, and transmission means for transmitting the encrypted contents signal and the identification information; and a second contents processing device including receiving means for receiving the encrypted contents signal and the identification information, decoding means for decoding the encrypted contents signal, and identification information appending means for appending the identification information to the contents signal decoded by the decoding means.
Moreover, a contents processing system according to the present invention includes: a contents processing device including decoding means for decoding an encrypted contents signal by a contents key, log information generation means for generating log information every time the contents key is decoded by the decoding means, storage means fro storing the log information, and transmission means for transmitting the log information at predetermined timing; and an accounting device including receiving means for receiving the log information, and accounting means for carrying out accounting based on the log information.
Also, a contents signal receiving method according to the present invention includes the steps of: receiving an encrypted contents signal; storing the received encrypted contents signal; decoding the stored encrypted contents signal when an instruction to decode the stored encrypted contents signal is given as user-designated information; and appending identification information to the decoded contents signal.
Furthermore, a contents signal receiving method according to the present invention includes the steps of: receiving an encrypted contents signal and identification information from outside; decoding the encrypted contents signal; and appending identification information to the decoded contents signal.
Also, a contents processing method according to the present invention includes the steps of: decoding an encrypted contents signal using a contents key; generating log information every time the contents key is decoded; storing the log information; and transmitting the log information at predetermined timing.
Also, a contents processing method according to the present invention includes the steps of: receiving an encrypted contents key obtained by encrypting a contents key for decoding an encrypted contents signal by using a distribution key updated every predetermined period; decoding the encrypted contents signal by the contents key; generating accounting information concerning the use of the encrypted contents signal; storing the accounting information; and transmitting the accounting information when the distribution key is updated.
Also, a contents processing method according to the present invention includes the steps of: receiving a distribution key, which is a key for decoding an encrypted contents signal and is updated every predetermined period; decoding the encrypted contents signal on the basis of the distribution key; generating accounting information concerning the use of the encrypted contents signal; storing the accounting information; and transmitting the accounting information when the distribution key is updated.